Process of making calcium cyanamid.



-F. S. WASHBURN. rnocnss- OF MAKING CALCIUM G'YANAMID;

, APPLICATION FILED JUNE 27, 1911.

Patented Nov. 21, 1911.

am 0044M (Mom I wasnsunm or NASHVILLE, TENNESSEE,

ASSIGIIOB- '10 AMERICAN GYLN- .AMIID COMPANY; OF BALTIMORE, A CORPORATION 03 ml,

rnocnss OF MAKING 'CALCIIIM crsimmn Specification of Letters Patent, Patented NOV. 21., 1911."

Original 'spplication'flled March 4, 1910, Serial No. 547,357. iDivld'cd and this application filed June 27, e

.I 1811. Serial No. assess.

Toall whom it may concern. 7

Be it known that I, FRANK'S. lVAsHnURN, a citizen of the United States, residing at Nashville, in the county of Davidson and State of Tennessee, have invented certain new and useful Improvements in Processes for Making'Calcium Cyanamid; and I do hereby declare the following to be a full, clear, and exact descriptionof the-invent'ion, such as will enable others skilled in the art to which it appertains to make. and use the same.

This invention relates to a process of producing calcium cyanamid in ovens or retQrts and} has for its object the improvement of the method of compelling the reaction be tween the nitrogen and'carbid, and for holding the same-in position during its manufacture, thereby not only improving the uniformity of the product but also producing a greater yield ofcalciuni cyanamid.

In. the retorts' l3 .retofore employed the central open space through thejmass of carbid has not been as eflicien't as hasbeendesired in affording va ready means for the nitrogen gas to attack the finely divided carbid, and, therefore, itl has been found desirable in practice to im rove this means. And, further, in the ol er methods, after the reaction is once started any passages which might have existed between the outer walls of the mass of carbid and the inner walls of the retort were soon more or less obstructed and, therefore, thek-free passage of the nitrogen in-a measure out 01f. i

This invention is a division of my prior, co pending application #547,857, filed March 4,1910, entitled Apparatus for producing" calcium cyanamid, now Patent No. 999,071, dated July 25, 1911, and it obviates these objections, and consists in the novel steps constituting the process more fully hereinafter set forth and particularly pointed out in the claims.

Referring to the accompanying drawings.

forming a part of this specification, in'which like numerals refer to likeparts' in all the views :Figur e 1, is a diagrammatic view illustrating 111 longitudlnal section, an oven,

suitable for carrying out this invention; Fig. 2, is'a transverse sectional view eithearts shown in Fig. l Fig. 3, is a view simia! to ibut. illustrating a slightly modi-- fied form ofmeans for holding the carbide and, Fi 4, is a sectional view of a portion of the oraminousvessel.

, 1 illustrates any suitable retort or vessel,

2 any suitable means for introducing nitrogen gas into-the vessel 1, 3 any suitable closure for said vessel, and 4: any suitable means for creating the desired tem era-ture inside the vessel, in this instance s own as a resistance heater connected to the lead wires 5 and '6. 4 i

As stated above, ithas heretofore been customary torovide cent-rally through the ,massmf car id 7 a space 8 through which the nitrogen gas passed and attacked the 1 car-bid all-around thesame, But it has been found in practicethat the assages of the nitrogeninto the interior of the mass soon became clogged with the result that thereaction was found to'have-been imperfectiin the. center of the mass; To obviate these objections, I provide a su table foraminous can or vessel 9 preferably made of wire cloth and.

suitably supported as by the brackets" or other supports 10 on the interior of the vessel 1." The" bottom of, the foraminous vessel 9 may be of the same material as the otter wal'l o 'r'o'f any other suitable foraminous or perforated substance. Thi'ough the center of the ivessel' 9, I hollowt'ube 11 inclosing the space 8* through which nitrogen may be freely passed, and if aresistarree heater such as 4 is employed said heatermay also be located in said tube 11, as

illustrated..- The vessel 9. is preferably head. e vessel 1 'y' away from ,the inside .offt brackets, such, as 12 in order to leave an annular space 13 in which the nitrogen may 'freely'circulate,

The calcium carbidis preferably used in provide i a foraminqus a. finely divided condition, and, therefore, it

' is liable to find its vWay throughthe walls of the vessely9 and tube 11. In order to preventthis,.-I preferto line the interior of the l vessel 9 and to cover the exterior of the tube 11 with layers of corrugated paper 14:, as illustrated, i

In theform shown in lh'g. -3,'instead of netting 9 as at 20 and permit the out-v wardly projecting portions of the same-to contact with the vinterior wall of the retort 1,118 will be clear'from an inspection of said the brackets 12' I may-corrugate the wireplace. This reaction, as it wcllknown', is

- companying. by-.products,-' chiefly-* free ear-. 2O

.mass of powdered carbide In fact, it is completely around as well as throughthe figure. In such case the'paper 21 maybefree passa es for the nitrogen, andther'eby the yield is also much greater, than it has 'been'possible to attain with the old style .of

tions being otherwise identical, thecans smooth, as'indicated, or itmay be corrugated, if desired.-

1. I The operation of the'retort willf be obv1, ous from the foregoing but may-be briefly summarized as followsi Upon v admitting nitrogen through the tube 2 and upon turning on the current through the resistance heater 4, or upon otherwise raising the. temperature of the interior of the vessel'gi'l, to the re: quired degree, the 'now well known reactionbetween the 'nitrogenand .carbidwill take strongly exort-hermic and when 'onc'e started, the reaction will continue cit-henwithout the aid of heater with some slight assistance therefrom until the entire mass is trans-' formed into calcium; 'cyanamid' and its action and free lime. 1A5 thetemperature rises the paper 14 or 21, as the case may be,'will, become charred so that the nitrogen is freely admitted through the same, while at the same time, thepowderedfcarbid now par-- tially converted into calcium cyanamid will not pass through the perforations of the vessel 9. 'The spaces 8 and 13 being kept always open by thewirecloth will "afford a means 't roughout the reaction by which the nitrogen may pass throughthe entire preferred to also maintain spaces 23 at the bottom and 24: at the top ofthe can 9 so that the nitrogen may at all times freely pass center of the mass of carbid. It resultsfro'm this structure that the reaction is not only much quicker than has heretofore been the case, but it is very much more perfect and.

retort. This is shown by the fact that in actual practice when using a screen made of wire of about one sixteenth of an inch in diameter, woven so as to form a mesh of and 34 retorts with these'screens, the condi without. the screensresulted in .5815 hours in an average of combined nitrogen amount-f ini; to 17 percent. of the weight of their contents. On the other hand, the retorts with the screens, under identical conditions,-

resultedafter 45.6;hours in' an averageofj addition to this, the cans The difference between these results is made.

clearer when it is stated that the retorts without screens combined the mt-rogen at .the rateof 3.15 pounds perhour, while the cans'with screensc'ombined the nitrogen at the rate of4.72.po und's" per hour, which, 1s a gain- .of about. 53- percent. over the old It is clear thatz'thisprocessm'a 'be carried out by apparatus entirely, di ererit fromthat disclosedpforthat itsessential characteristicseonsist in maintaining at all times .a free passage forthenitrogen through and around the mass; o ffcarbid, while, of course,

providing a 'm' ns'y'j-fortm nitrogen to readily enter thelhodyj of the mass of carbid.

'Itis therefore obyious-that those "skilled in the art may.varytztheidetails' of construction and .arrangementofgparts without departing from the .spirit of my proc'ess,=.and therefore,-I do? not w'islr'to be limited to such ffeatures, exceptfias may be required'by the claims. a I

1.,.The processof producing calcium cyanam'id from calciunicarbid, which consists in providing-a mass 9f said 'carbid in a finely divided condition; in surrounding said finely dividedparbid with a readily combustible envelop '.i n providing and maintaining-a free passage for nitrogen through the body of-.- sai d' 1 mass; and, insubjecting said mass to the requisite temperature in the presence of free nitrogen to carbonize the envelop and'tofo'rni said cyanamid, substantially as described.

2. .The proces's'qpf. increasing the /yield and improving1the qua lity of calcium cyanamid during the manufacture of the same,

g which consists in providing'amass of finely about three-slxteenths of'an inch square andemploying 89 retorts without these-screens divided calcium jc'arbid; in proxiding' and maintaining :Ipassages. '1 for nitrogen through and around said mass during the reaction; and inheating said mass to the temperature.- required to produce calcium ,cyanamid' in 'the -gpresence offree substantially. as described;

nitrogen, 

